How can I make Blender put less strain on my CPU?
If 90% of CPU load bothers you, ie its not comfortable to work with other programs, you can set priority to the Blender by Task Manager.

Press Ctrl+Shift+Esc to launch Task Manager.

Prior Windows 10, right click on Blender process->Set Priority->Low. In the Windows 10 select details tab, and again right click on Blender process->Set Priority->Low